Stag IV heads

[TerryC]

Need information concerning Mopar stage IV cast iron heads. I've got a set that has been professionally ported, 30 years ago and have never been used. I was thinking of using them with 12.5 compression pistons/E85 fuel. Any suggestions ?

 

[Cranky]

Go for it if you already have them. They were supposed to have more meat in the castings so you could port them out without fear of cracking like usually happened on 906 max ported heads and iirc, they had better ports than regular factory castings. Been a very long time since I had a pair of those laying around.

 

[lewtot184]

find some of the old direct connection books for details. should be better than a '906. the issue i would have is a domed high compression piston. make sure the dome doesn't enclose/shroud the spark plug. the IV is an open chamber head and has quench issues.

 

[2059]

Run 'em. Use best pump gas 92 plus. Manage your timing and see how it goes..

 

[Cranky]

find some of the old direct connection books for details. should be better than a '906. the issue i would have is a domed high compression piston. make sure the dome doesn't enclose/shroud the spark plug. the IV is an open chamber head and has quench issues.

Yup, they are better than the 906 head out of the box and open chamber. IIRC, they were supposed to have a bit smaller cc than the rest of the factory open chamber heads but the ones I had didn't check out that way.

 

[lewtot184]

Yup, they are better than the 906 head out of the box and open chamber. IIRC, they were supposed to have a bit smaller cc than the rest of the factory open chamber heads but the ones I had didn't check out that way.

same chamber size as 906 and stage V.

 

[mentor70]

if your looking for big power, and a big displacement, im going against the grain here and say Junk them...lots of cheap Aluminum options that flow better, even after porting.

but knowing what the rest of the engine gonna be like, anything you already own will work.